1. Field of the Invention
The present invention relates to agricultural harvesters such as combines, and, more particularly, to auger assemblies used in such combines.
2. Description of the Related Art
An agricultural harvester known as a “combine” is historically termed as such because it combines multiple harvesting functions with a single harvesting unit, such as picking, threshing, separating and cleaning. A combine includes a header which removes the crop from a field, and a feeder housing which transports the crop matter into a threshing rotor. The threshing rotor rotates within a perforated housing, which may be in the form of adjustable concaves and performs a threshing operation on the crop to remove the grain. Once the grain is threshed it falls through perforations in the concaves onto a grain pan. From the grain pan the grain is cleaned using a cleaning system, and is then transported to a grain tank onboard the combine. When the grain tank becomes full, the combine is positioned adjacent a vehicle into which the grain is to be unloaded, such as a semi-trailer, gravity box, straight truck, or the like; and an unloading system on the combine is actuated to transfer the grain into the vehicle.
Typical unloading systems for combines involve unloading augers that are formed from inner and outer tubes (relative to the chassis of the combine) with rotatable augers inside that can be actuated to move grain longitudinally through the tubes. The tubes are pivoted to the combine so that they may be displaced laterally relative to the movement of the combine to an unload position in which grain is deposited in a wagon or other vehicle for transport. When the unloading function is completed, the auger tubes are retracted to a fold position in which the inner auger tube is generally parallel to the longitudinal axis of the combine and the outer auger tube is bent to an angle in a horizontal plane so that its free end is maintained within the overall configuration of the combine.
The auger tubes each have longitudinally extending augers within them that are mounted for rotation so that crop material is moved longitudinally through the augers. Because the auger tubes are pivoted between the unload and fold position, it is necessary to provide a mechanical coupler between the drive auger in the inner auger tube and the driven auger in the outer auger tube that delivers crop material to a transport vehicle. In the past, the coupling between the two augers has been provided by single projections at the end of each auger that interact and abut to cause the outer auger to be driven. With prior auger designs, the initial coupling of the auger tubes in the driving position causes, under certain circumstances, a movement of the projection into place and subsequent rotational displacement that can be close to a complete circle. The rotational displacement causes an opportunity for accelerated impact between the two projections, thus having an effect on long term wear.
Accordingly, what is needed in the art is an auger coupling mechanism that minimizes acceleration forces upon engagement.